package main

func main() {
	a := 1
	println(a)

	DoOperation(1, increase)
	DoOperation(1, decrease)
}

func increase(a, b int) {
	println("add result is:", a + b)
}

func DoOperation(y int, f func(int, int)) {
	f(y, 1)
}

func decrease(a, b int) {
	println("decrease result is:", a - b)
}
